Sifting apparatus



' (No M5661.)

H. SEGK. sIPTI-NG APPARATUS.

No. 536,546. Patented Mar. 26, 1695.

UNITED STATEsf PATENT OFFICE.

HEINRICH -sEcK, or DRESDEN, GERMANY.

,t sll-TlNG APPARATUS.

SPIEICIFICATIOLT forming part of Letters Patent N o. 536,546, datedMarch 26,1895.

Application filed October 9,1894. Serial No. 525,401. (No model.)

T0 If/ZZ whom it may concern.-

Be it known that I, HEINRICH SECK, of Dresden, in the Kingdom of Saxonyand German Empire, have invented a certain new and useful Improvement inSifting Apparatus, of which the following is a specification.

This invention relates to sifting machines, and more particularly tomachines of the class generally known as centrifugal sifting machines,said machines usually embodying a rotatable frame or casing, spannedwith bolting cloth, and a frame rotatably mounted therein and providedwith wings or beaters which, upon the said frame being rotated, act, inconjunction with the centrifugal force, to throw the material to besifted against the inner surface of the bolting cloth. As is well known,the said wings may either extend spirally in a longitudinal direction,or they may be twisted, pitched or set so as thereby to cause thematerial to be conveyed through the machine in a longitudinal direction.The sifting machines of this class as heretofore generally constructed,have presented th'is objection that the wings, while propelling thematerial outwardly and, at the same time, conveying the same through themachine, would allow a comparatively limited portion only of the surfaceof the bolting cloth to perform a proper sifting action, while by farthe greater part of the sifting surface would remain out of contact withthe material to be sifted. The object of my present invention is toremove this objection and to provide means for securing a more efficientsifting effect in machines of this class, and, at the same time, tosecure other advantages which will be more fully hereinafter referredto.

My invention, therefore, consists in providing between each two of thepropelling wings of a centrifugal sifting machine, one or moreadditional or auxiliary elevating or sucking wings or blades, the saidauxiliary wings being so arranged as to properly seize the material andto allow it to slide down along the inner surfaces to be thereunderseized by the propelling wings and thrown against the sifting surface,the said auxiliary wings also acting to produce an air draft and, thus,regular pulsations of air which assist in causing the material to beproperly brought under the ac- A tion of the propelling wings, and whichproduce a most efficient sifting action, thematerial beingby these meansequally distributed over, andbrought into thorough contact with, theentire sifting surface.

In the accompanying drawings illustrating my invention Figure l is avertical longitudinal section (on the line -x of Fig. 2) of a sufficientportion of a sifting machine provided with my improvements, to renderthe arrangement and operation thereof properly understood. Fig. 2 is acorresponding vertical transverse section, and Fig. 3 any enlargedsectional view of a peripheral portion of the drum showing thearrangement of the propelling and of the auxiliary wings thereon.

A illustrates the rotary frame or casing spanned with bolting cloth.Within the same is journaled the drum B, the latter being either ofcylindrical shape, as shown, or having a polygonal or other suitablecross section, and having rotary movement imparted to it by any suitableand well known means. The said drum is provided with. the propellingWings a. each of which may be either slotted or formed with a continuoussurface, as may be desired. Between each two of these propelling wings aare mounted the auxiliary elevating or sucking wings b, the samerbeingpreferably 'secured to the drum in the manner illustrated moreparticularly in Fig. 3, and otherwise essentially conforming in shape tothe wings ct. c are slits or apertures provided in the walls of the drumB.

The operation of the drum provided with my' improved arrangement ofwings as described, is as follows, that is to sayz-Upon the drum B beingrotated the auxiliary elevating wings b will lift the material to besifted and will then, during their upward movey ment, allow the same toslide down along the same along their inner surfaces, as indicated inFig. 2. The said material will thereupon he seized by the propellingwings a and thrown against the inner surface of the sifting or boitingcloth on the frame A. The auxiliary wings b, acting to displace the airfrom within the space cl contained between themselves and the saidpropelling wings a, will produce within such space a certain rarefactionof the air, thereby causing a current of air which will convey thematerial to the lifting or elevating wings a. The latter will,

lOO

at the same time, produce a pressure current of air moving in a radiallyoutward direction. A continual change of air will thus take placebetween the drum B and the sifting surface, producing regular pulsationsand causing a most efficient sifting action while, at the same time,tending to keep the sifting surface open. It will be seen that by thiscompound arrangement of wings in a sifting machine, as described, thematerial to be sifted will be thoroughly distributed over the entiresifting surface, so that the entire area of its inner peripheral surfacewill be brought into action, while with the arrangement of Wings asheretofore generally employed by far the greater part of the saidsurface would remain practically ont of action and a comparatively1imited portion only would be utilized for actual sifting.

Having thus fully described my invention,

what I desire' to claim and secure by Letters Patent is In a centrifugalsifting machine, the combination with the rotary frame or casing Aprovided with a sifting surface, of the inner rotary drum B surroundedby said sifting surface and provided with the air slits c, and having onits outer side the propelling wings a, adjacent to the air slits and thediagonally arranged auxiliary elevating or sucking Wings b,"':mountedbetween each two of the propelling wings, substantially as and for thepurposes described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

HEINRICH SECK.

Witnesses:

HERNANDO DE So'ro, PAUL ARRAS.

